A vehicle featuring a downsized, supercharged engine (hereinafter, referred to as a downsized, supercharged vehicle) enhances fuel efficiency by adopting a small displacement turbocharged engine and is in widespread use recently. The downsized, supercharged vehicle preferably uses a water-cooled intercooler to cool supercharged air. The water-cooled intercooler is preferable because a capacity of an inlet system can be smaller than in a case where an air-cooled intercooler is used and therefore an engine response can be better.
Patent Document 1 describes a configuration in which coolant water supplied from a turbocharger cooling system flows through a water-cooled intercooler. The turbocharger cooling system is an independent water-cooled cooling system provided separately from an engine cooling system.
In the turbocharger cooling system, coolant water is supplied to the water-cooled intercooler as the coolant water is circulated by a water pump. Driving of the water pump is controlled according to an engine operation state depending on an engine speed, an engine water temperature, an intake air temperature, and so on.
In the related art, when intake air is cooled to or below a dew-point temperature in the water-cooled intercooler, condensed water is generated from the intake air and the condensed water is drawn into an engine with the intake air. When a large amount of condensed air is drawn into the engine, an adverse effect given to an engine operation may possibly cause an engine misfire or the like and also corrosion may develop in the intercooler.